Universities UK chief executive Alistair Jarvis said: "There is already a legal duty on the higher education sector to secure free speech within the law and universities take these responsibilities very seriously."

He added that institutions also had a duty of care to the "safety of students and staff".

Sir Anthony Seldon, the vice-chancellor of the University of Buckingham, agrees with Mr Johnson's plan, saying it is a "duty" of universities to "open up dialogue".

But he says it is "degrading" that the minister has had to step in.

"The universities themselves autonomously didn't get their eggs in order, so the universities minister is having to tell us what to do," he told the BBC News Channel.

"I think that really is quite a shame for us, and almost rather degrading that we're in that position."

Image caption
The study on the ethics of the British Empire is taking place at Christ Church, Oxford

Mr Johnson's speech comes as one of the UK's oldest universities has been criticised by academics for a project on the ethics of the British Empire.